Editor's note: "The First 90 Days" is a series about how to make 2016 a year of breakout growth for your business. Let us know how you're making the first 90 days count by joining the conversation on social media with the hashtag #Inc90Days.​

Running a business puts persistent pressure on you to pay your bills on time.

If you fail to pay, your employees will quit, your suppliers will cut you off, your bank will take control of your assets, and all that bad news will spook your customers and they'll take their business elsewhere.

While these disastrous outcomes are not hard to foresee, plenty of business leaders make mistakes when it comes to managing company finances.

Here are five of the most common money mistakes, and how not to make them.

1. Letting cash reserves get too low

Many business owners are optimistic. That's great if you're trying to convince customers and employees to join you in building your business.

But optimism can get business owners in trouble unless they are both optimistic and fiscally conservative.

A very common business mistake is to underestimate how much cash you will need to get your business off the ground and to run things once you start generating revenue.

To figure out how much cash to keep on hand, I tell executives to make a detailed checklist of all the cash they'll need, add up all the items, and then double that number.

2. Spending money on things that don't matter

Business owners who have recently persuaded investors or a bank to give them money too often want to broadcast their good fortune by taking office space in an expensive building that tells the world they've made it.

This is the small business equivalent of the edifice complex--a disease that afflicts companies that feel compelled to name a football stadium or erect a huge headquarters building.

As the late Intel co-founder Andrew Grove admonished, only the paranoid survive.

If you remain paranoid--instead of deluding yourself that a capital raise means you are on easy street--then you'll manage that money as if it was the last investment your company will ever get.

And if you maintain your intellectual humility, you'll realize that you should only spend money on things that are essential for your company's growth and stay away from spending on what bolsters your fragile ego.

3. Failing to forecast cash requirements

Your employees and suppliers expect to get paid on time.

But too many companies fail to maintain an accurate and up-to-date cash flow forecast. This failure can cause you to suffer the unpleasant surprise of not having enough cash to pay your bills when they're due.

And that could cause trust to evaporate and put you in a tight spot--forcing you to pay high fees and interest rates to get the quick cash you need.

The remedy for this problem is simple to describe--build and use a cash forecasting system that is always accurate--and hard to do.

If you don't do this yourself, put someone in charge of cash forecasting who is meticulous and persistent.

4. Scrimping on accounting services and financial systems

A basic principal of organizations is that you get what you measure.

Too many business owners don't care much for accounting services and financial systems, so they don't invest in them.

But the absence of top-notch accounting could get you in trouble and make it more difficult to run your business.

Hire a good accountant and run excellent financial systems so you are free to focus on building new products, hiring the right people, and getting and keeping customers.

5. Being too passive on cash collections

Another common--and costly--mistake is assuming that your customers will pay you on time.

Executives may be afraid to alienate their customers by pushing them to pay what they owe when it is due.

But you ought to explain to those customers that paying you on time helps you to keep your operation running smoothly so that it can keep serving them well.

If your business is helping to make your customers more successful, then they will appreciate this logic.

Take these steps to avoid the five most common money mistakes, and your business will be able to invest in new products that keep your company growing for years to come.